// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_MISC_IMAGE_H
#define EIGEN_MISC_IMAGE_H

namespace Eigen {

namespace internal {

/** \class image_retval_base
 *
 */
template<typename DecompositionType>
struct traits<image_retval_base<DecompositionType>>
{
	typedef typename DecompositionType::MatrixType MatrixType;
	typedef Matrix<typename MatrixType::Scalar,
				   MatrixType::RowsAtCompileTime, // the image is a subspace of the destination space, whose
												  // dimension is the number of rows of the original matrix
				   Dynamic,						  // we don't know at compile time the dimension of the image (the rank)
				   MatrixType::Options,
				   MatrixType::MaxRowsAtCompileTime, // the image matrix will consist of columns from the original
													 // matrix,
				   MatrixType::MaxColsAtCompileTime	 // so it has the same number of rows and at most as many columns.
				   >
		ReturnType;
};

template<typename _DecompositionType>
struct image_retval_base : public ReturnByValue<image_retval_base<_DecompositionType>>
{
	typedef _DecompositionType DecompositionType;
	typedef typename DecompositionType::MatrixType MatrixType;
	typedef ReturnByValue<image_retval_base> Base;

	image_retval_base(const DecompositionType& dec, const MatrixType& originalMatrix)
		: m_dec(dec)
		, m_rank(dec.rank())
		, m_cols(m_rank == 0 ? 1 : m_rank)
		, m_originalMatrix(originalMatrix)
	{
	}

	inline Index rows() const { return m_dec.rows(); }
	inline Index cols() const { return m_cols; }
	inline Index rank() const { return m_rank; }
	inline const DecompositionType& dec() const { return m_dec; }
	inline const MatrixType& originalMatrix() const { return m_originalMatrix; }

	template<typename Dest>
	inline void evalTo(Dest& dst) const
	{
		static_cast<const image_retval<DecompositionType>*>(this)->evalTo(dst);
	}

  protected:
	const DecompositionType& m_dec;
	Index m_rank, m_cols;
	const MatrixType& m_originalMatrix;
};

} // end namespace internal

#define EIGEN_MAKE_IMAGE_HELPERS(DecompositionType)                                                                    \
	typedef typename DecompositionType::MatrixType MatrixType;                                                         \
	typedef typename MatrixType::Scalar Scalar;                                                                        \
	typedef typename MatrixType::RealScalar RealScalar;                                                                \
	typedef Eigen::internal::image_retval_base<DecompositionType> Base;                                                \
	using Base::dec;                                                                                                   \
	using Base::originalMatrix;                                                                                        \
	using Base::rank;                                                                                                  \
	using Base::rows;                                                                                                  \
	using Base::cols;                                                                                                  \
	image_retval(const DecompositionType& dec, const MatrixType& originalMatrix)                                       \
		: Base(dec, originalMatrix)                                                                                    \
	{                                                                                                                  \
	}

} // end namespace Eigen

#endif // EIGEN_MISC_IMAGE_H
